/*
 * Copyright (C) 2002, 2003 Philip Blundell <philb@gnu.org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <stdio.h>
#include <string.h>

#include <X11/Xlib.h>
#include <X11/Xatom.h>

#include <gdk/gdk.h>
#include <gdk/gdkx.h>
#include <gtk/gtk.h>

#include <libintl.h>

#define _(x) dgettext(PACKAGE, x)

static GdkAtom help_atom;
static gboolean gpe_what_initialised;

void gpe_what_mark_widget (GtkWidget *widget);

GSList *widgets;

static void
send_text (Display *dpy, Window w, char *text)
{
  Atom help_xatom = gdk_x11_atom_to_xatom (help_atom);

  gdk_error_trap_push ();

  XChangeProperty (dpy, w, help_xatom, XA_STRING, 8, PropModeReplace, text, strlen (text));

  XFlush (dpy);

  gdk_error_trap_pop ();
}

static GdkFilterReturn 
filter_func (GdkXEvent *xev, GdkEvent *ev, gpointer p)
{
  XClientMessageEvent *xc = (XClientMessageEvent *)xev;
  GSList *list;
  Window sender = xc->data.l[0];

  for (list = widgets; list; list = list->next)
    {
      GtkWidget *widget = GTK_WIDGET (list->data);
      int x = xc->data.l[1], y = xc->data.l[2];
      int ax, ay;
      
      if (!GTK_WIDGET_DRAWABLE (widget)) continue;
      
      if (GTK_WIDGET_NO_WINDOW (widget))
	{
	  ax = widget->allocation.x;
	  ay = widget->allocation.y;
	}
      else
	{
	  ax = 0;
	  ay = 0;
	}

      if (widget->window == ev->any.window
	  && x >= ax && x < ax + widget->allocation.width
	  && y >= ay && y < ay + widget->allocation.height)
	{
	  GtkTooltipsData *data = gtk_tooltips_data_get (widget);
	  send_text (GDK_WINDOW_XDISPLAY (widget->window), sender, 
		     data->tip_private ? data->tip_private : data->tip_text);
	  return GDK_FILTER_CONTINUE;
	}
    }

  send_text (GDK_WINDOW_XDISPLAY (ev->any.window), sender, _("No help available."));

  return GDK_FILTER_CONTINUE;
}

void
gpe_what_mark_widget (GtkWidget *widget)
{
  if (gpe_what_initialised)
    {
      if (widget->window)
	{
	  widgets = g_slist_prepend (widgets, widget);
	  
	  gdk_property_change (widget->window,
			       help_atom,
			       help_atom,
			       8,
			       GDK_PROP_MODE_REPLACE,
			       NULL,
			       0);
	}
      else
	g_signal_connect_after (widget, "realize", G_CALLBACK (gpe_what_mark_widget), NULL);
    }
}

void
gpe_what_init (void)
{
  help_atom = gdk_atom_intern ("_GPE_INTERACTIVE_HELP", FALSE);

  gdk_add_client_message_filter (help_atom, filter_func, NULL);

  gpe_what_initialised = TRUE;
}